Diagnostic approaches for pancreatic cystic lesions

Comparison of Preoperative Imaging Modalities for the Assessment of Malignant Potential of Pancreatic Cystic Lesions: A Network Meta-analysis

PURPOSE

The aims of this study are to compare the performance of various preoperative imaging modalities for assessing the malignant potential of pancreatic cystic lesions (PCLs) through a network meta-analysis (NMA) and to clarify the role of 18 F-FDG PET in the management of patients with PCL.

METHODS

PubMed, EMBASE, and Cochrane Library were searched for the studies evaluating the performance of preoperative imaging modalities for identifying malignant PCLs. The NMA was performed for 4 representative categories of various imaging modalities in terms of diagnostic performance for differentiating malignant from benign PCL and intraductal papillary mucinous neoplasms only as a subgroup analysis. To calculate the probability of each imaging modality being the most effective diagnostic method, the surface under the cumulative ranking curve values were obtained.

RESULTS

A total of 1018 patients from 17 direct comparison studies using 2 or more preoperative imaging modalities were included for differentiating malignant from benign PCL. The positive predictive value (PPV) and accuracy of 18 F-FDG PET were significantly higher than that of CT (PPV: odds ratio [OR], 2.66; 95% credible interval [CrI], 1.21-6.17; accuracy: OR, 2.63; 95% CrI, 1.41-5.38) or MRI (PPV: OR, 2.50; 95% CrI, 1.09-6.26; accuracy: OR, 2.50; 95% CrI, 1.28-5.47) in all PCLs, as well as in the subgroup analysis for intraductal papillary mucinous neoplasm only. 18 F-FDG PET showed the highest surface under the cumulative ranking curve values in all diagnostic performance areas of sensitivity, specificity, PPV, negative predictive value, and accuracy, followed by MRI or CT.

CONCLUSIONS

The results from this NMA suggest that 18 F-FDG PET is the best preoperative imaging modality for differentiating malignant from benign PCLs and that it can be used for the preoperative evaluation of PCLs.

Advances in the Diagnosis of Pancreatic Cystic Lesions

Pancreatic cystic lesions (PCLs) are a heterogenous group of lesions ranging from benign to malignant. There has been an increase in PCLs prevalence in recent years, mostly due to advances in imaging techniques, increased awareness of their existence and population aging. Reliable discrimination between neoplastic and non-neoplastic cystic lesions is paramount to ensuring adequate treatment and follow-up. Although conventional diagnostic techniques such as ultrasound (US), magnetic resonance imaging (MRI) and computer tomography (CT) can easily identify these lesions, assessing the risk of malignancy is limited. Endoscopic ultrasound (EUS) is superior to cross-sectional imaging in identifying potentially malignant lesions due to its high resolution and better imaging characteristics, and the advantage of allowing for cyst fluid sampling via fine-needle aspiration (FNA). More complex testing, such as cytological and histopathological analysis and biochemical and molecular testing of the aspirated fluid, can ensure an accurate diagnosis.